Why do i try so hard and never see any benefits or improvements in my health?

I'm 18 and love finding new ways i can naturally nourish and help my body be healthy. I'm a hypochondriac and i always seem to have something hurting on me. A few weeks ago it was itchy skin, that got worse when i thought about it, and dissapeared when i forgot about it. the following thing was eye floaters, the same thing happened i didnt see as many wehen i forgot about them. Now im worried about my wisdom tooth, it has been growing for over a year, and there is plenty of room for it to grow, over a centimetre, but randomly the other day it started feeling a bit sore and now because i've worried so much i barely move my mouth cos im scared. My twin sister never had anything barely wrong with her and she is more unhealthy than me! Why?